This application claims benefit of Japanese Application No. 2000-66214 filed in Japan on Mar. 10, 2000, the contents of which are incorporated this reference.
The present invention relates to solid-state image pickup apparatus and fabricating method thereof having a solid-state image pickup device chip packaged in a hermetic seal.
A conventional solid-state image pickup apparatus having light receiving sensor chips such as a solid-state image pickup device chip in a hermetically sealed package is generally constructed as shown in FIG. 1. In particular, a solid-state image pickup device chip 101 is die-bonded to a package 102 for example of ceramics and a bonding wire 103 is used to achieve predetermined electrical connections between the solid-state image pickup device chip 101 and package 102. A space from the surface of the device chip 101 is provided by using step 104 formed at edge portions of package 102 and a hermetic seal is achieved by adhering a glass lid 105 thereto to construct the solid-state image pickup apparatus. It should be noted that numeral 106 in FIG. 1 denotes an external lead.
In solid-state image pickup apparatus having such construction, use of package 102 and glass lid 105 for hermetically sealing the entire solid-state image pickup device chip resulted in an increased packaging size and thus had been difficult to be applied to the fields where smaller package size was required.
To eliminate such disadvantage, the present applicant had proposed solid-state image pickup apparatus constructed as disclosed in Japanese patent laid-open application Hei-7-202152. A sectional view of such solid-state image pickup apparatus is shown in FIGS. 2 and 3. In FIG. 2, only the light-receiving area on the solid-state image pickup device chip 101 is hermetically sealed by means of a sealing member which includes a flat-plate portion 107 made of a transparent member and a frame portion 108 integrally formed therewith at a lower surface edge thereof. Glass, quartz, sapphire, transparent resin or the like is used as the transparent member for constituting the flat-plate portion 107. In the solid-state image pickup apparatus shown in FIG. 3, on the other hand, instead of integrally forming a hermetic seal portion, a flat-plate portion 109 and a frame portion 110 are adhered to each other to constitute the hermetic seal portion. Here frame portion 110 may be constituted by such inorganic materials as ceramics, glass, silicon or such metal as Kovar or 42-alloy. Further, it is also possible that an epoxy, phenol, or silicone resin may be printed or pattern-formed by photolithography on the surface of the solid-state image pickup device chip 101 to form the frame portion 110.
By constructing solid-state image pickup apparatus in this manner, a smaller size packaging thereof is possible and, especially in a solid-state image pickup apparatus having a micro-lens, the solid-state image pickup apparatus can be achieved without degrading the light converging capability of the micro-lens even when such optical components as a filter, lens, prism, etc., is adhered to the surface of the hermetic seal portion. Further, fabrication method has also become simpler, since hermetic seal portions can be formed at once for all of a large number of solid-state image pickup device chips in a wafer.
The previously proposed solid-state image pickup apparatus as described above, however, has the following problems to be solved. First, the structure of the integrally formed, hermetic seal portion as shown in FIG. 2 requires an integral forming of the hermetic seal portion having a flat-plate portion and a frame portion by using such transparent material as glass. Precision in processing is thus required and difficulties such as an increased the amount of work in fabrication are foreseen.
Further, the method of constructing the hermetic seal portion by adhering flat-plate portion and frame portion to each other as shown in FIG. 3, especially the method of constructing the frame portion by means of a pattern forming of resin, requires the processing steps of forming a resinous pattern, i.e., application of the resin onto a wafer, printing or photolithography, developing and etching. There is thus a problem that the number of processing steps is increased.
Furthermore, a more serious problem presumably occurs with this technique when the solid-state image pickup apparatus has a micro-lens. This is because a micro-lens, usually, is formed also from a resin. For example, after applying a resin over the entire surface of a wafer, the processing steps of patterning and etching of the frame portion must be performed before the resin cures. If etching is performed before the curing of the resin, however, the resin capable of becoming the frame portion is also etched away similarly as the portion of resin to be removed and there is a possibility that a sufficient frame is not formed. If etched after the curing of the resin, on the other hand, though a desired shape for the frame is formed, there is a possibility that the micro-lens is etched away at the same time of the etching of the unnecessary portion of resin to be removed due to the fact that the micro-lens is also made of a resin.
As the above, those previously proposed are with problems in the fabrication method or the reliability of hermetic seal portion, even though smaller size packaging is possible and hermetic seal portions can be formed at once for all chips in a wafer.
To eliminate the above problems, it is a main object of the present invention to provide a solid-state image pickup apparatus which can be packaged in a relatively small size and at the same time has a simple construction and a reliable hermetic seal portion.
In accordance with the invention, there is provided a solid-state image pickup apparatus fundamentally including: a solid-state image pickup device chip; and a hermetic seal portion provided over the solid-state image pickup device chip having a flat-plate portion formed of a transparent member and a frame portion adhered to a lower surface edge portion of the flat-plate portion, the frame portion of the hermetic seal portion comprising an epoxy-type resin sheet.
By constructing as the above, the solid-state image pickup apparatus can be achieved by a simple construction capable of downsizing at the same time of having a highly reliable hermetic seal portion. The above main object is thereby accomplished.
It is another object of the invention to provide a solid-state image pickup apparatus having a hermetic seal portion based on a simpler construction not requiring an adhesive.
In a further aspect of the invention, the epoxy-type resin sheet of the frame portion of the hermetic seal portion of the solid-state image pickup apparatus of the above fundamental construction has an adhesive property.
By constructing as the above, an adhesive becomes unnecessary in the forming of hermetic seal portion so that the hermetic seal portion can be made easily using a simple construction. The above object is thereby accomplished.
It is yet another object of the invention to provide a solid-state image pickup apparatus in which shielding of unwanted rays of light at solid-state image pickup device can be effected without providing a separate member for shielding light.
In a further aspect of the invention, the epoxy-type resin sheet of the frame portion of the hermetic seal portion of the solid-state image pickup apparatus of the above fundamental construction has a function of shielding light based on coloring or the like.
By constructing as the above, the frame portion of hermetic seal portion is capable of shielding unwanted rays of light so that adverse effects due to stray light or reflection on solid-state image pickup device chip can be prevented without providing a separate member for shielding light. The above object is thereby accomplished.
It is still another object of the invention to provide an optimum electrical connection structure between solid-state image pickup device chip and an external terminal in solid-state image pickup apparatus having a hermetic seal portion.
In a further aspect of the invention, the solid-state image pickup apparatus of the above fundamental construction has a wiring region formed from an electrode pad provided on the solid-state image pickup device chip to a side surface or from the electrode pad to a reverse surface of the solid-state image pickup device chip through the side surface so that an external terminal can be electrically connected to the wiring region.
By constructing as the above, an optimum electrical connection structure can be achieved between the solid-state image pickup device chip and the external terminal. The above object is thereby accomplished.
It is another object of the invention to provide fabricating method of solid-state image pickup apparatus capable of readily forming a hermetic seal portion with high registration accuracy on solid-state image pickup device chip.
In accordance with a further aspect of the invention, a fabricating method of solid-state image pickup apparatus including a solid-state image pickup device chip and a hermetic seal portion provided over the solid-state image pickup device chip having a flat-plate portion formed of a transparent member and a frame portion adhered to a lower surface edge portion of the flat-plate portion includes the steps of: for an entire wafer having a large number of solid-state image pickup device chips formed thereon, integrally forming hermetic seal portion having a flat-plate portion made of a transparent member and a frame portion formed of an epoxy-type resin sheet adhered to a lower surface edge portion of the flat-plate portion correspondingly to respective solid-state image pickup device chips; separating the wafer having the integrally formed hermetic seal portion thereon into solid-state image pickup device chips each having an individual hermetic seal portion.
By using such processing steps, hermetic seal portions can be formed at once on respective solid-state image pickup device chips in a wafer. Accordingly, it becomes possible to readily fabricate a solid-state image pickup apparatus having a hermetic seal portion precisely over solid-state image pickup device chip.